1. Field of the Invention
This invention relates to an image recording apparatus which uses a photosensitive material formed by coating a support with a substance with which an image formed through optical exposure is fixed under pressure.
2. Background of the Invention
One example of an image recording material utilizing microcapsules containing photosensitive composites has been disclosed, for instance, by Japanese patent application (OPI) No. 179836/1982 (the term "OPI" as used herein means "an unexamined Japanese published application). The image recording material is made up of a layer of capsules having synthetic macromolecular resin walls and containing a vinyl compound, a photopolymerization initiator and a colorant precursor formed on a support. In a image recording method using the image recording material, the image recording material is optically exposed so that the microcapsules are selectively hardened according to an image to be formed. The microcapsules which have not been hardened are broken by pressure so that the colorant cursor discharged therefrom forms a colored image. This method is advantageous in that an image of high picture quality can be obtained by a simple dry treatment. However, the image recording material shows much lower photosensitivity than a material which utilizes silver halide.
A novel recording material which, eliminating the above-described difficulty, shows high photosensitivity and can provide an image high in picture quality has been disclosed by the specification of Japanese patent application (OPI) No. 275,742/1986, filed by the present applicant. The recording material is formed by coating at least photosensitive silver halide, reducing agent, polymerizing compound and color image forming material on a support. The polymerizing compound and the color image forming material form a photosensitive composite in one and the same microcapsule.
An image recording method of recording images with this photosensitive material has been disclosed by Japanese patent application (OPI) No. 278,849/1986 filed by the present applicant. In the method, the photosensitive material is subjected to optical exposure to form a latent image therein and is then heated for developing the latent image. As a result, the polymerizing compound in a part or parts of the photosensitive material where the latent image has been formed is polymerized to form a macromolecular compound to harden the microcapsules. Under this condition, the photosensitive material thus treated is stacked under pressure on an image-receiving material which has an image-receiving layer onto which the color image forming material can be transferred. As a result, at least some of the microcapsules at a part or parts of the photosensitive material where no latent image has been formed are broken so that the color image forming material is transferred onto the image-receiving material to obtain the image thereon.
An image recording apparatus for automatically practicing the above-described image recording method has been disclosed, for instance, by the specification of Japanese patent application No. 51,896/1986, filed by the present applicant.
FIG. 1 is a sectional view of image recording apparatus of this reference. The apparatus comprises an upper unit 3 and a lower unit 4. The upper unit 3 is an exposing device and accommodates an image-forming optical system 200. The lower unit 4 incorporates an exposed photosensitive material roll 26, a thermal developing device 40 and a transferring device 88. A photosensitive material S is processed while being conveyed in the lower unit 4.
However, the apparatus suffers from the following difficulty. Because of the synergistic effect of the installation accuracy of the image-forming optical system 200 in the upper unit 3, the installation accuracy of the exposed photosensitive material supporting roll 26 in the lower unit 4, and the assembly accuracy of the upper and lower units 3 and 4, the image-forming focusing position of the optical system sometimes greatly varies from the position of the photo-sensitive material S supported by the exposed photosensitive material supporting roll 26. Therefore, the image formed thereon through optical exposure is not distinct, being not accurately focused thereon, and the resultant record is low in picture quality.
Furthermore, in the conventional image recording apparatus of Japanese patent application No. 51896/1986, in order to prevent an increase of the size and to simplify the construction, the processing devices and the conveying means are driven by one and the same drive source, so that the variations of the loads of the processing devices and the conveying means are transmitted to one another through the drive system. This tendency is significant in the pressure transferring device. That is, in the pressure transferring device, the photosensitive material and the image-receiving sheet piled one on another are pressurized at 200 kg/cm.sup.2 or higher by a pair of pressurizing rolls. Therefore, when the photosensitive material and the image receiving sheet go into and come out of the pressurizing rolls, a great impact is exerted on the transferring device so that the device is vibrated and the speed of rotation of the rolls is changed. The variation of the load of the pressurizing rolls is transmitted through the drive source to the exposing device. As a result, in the exposing device the original scanning speed and the photosensitive material conveying speed are changed thus adversely affecting the optical exposure.
In the conventional image recording apparatus of Japanese patent application No. 51896/1986, the photosensitive material and the image-receiving material which have been subjected to pressure transferring are separated from each other and conveyed. More specifically, the image-receiving material is conveyed to a fixing device when necessary, and the photosensitive materials is delivered to a discarding section.
In general, the photosensitive material is larger in area than the image-receiving material. Therefore, the photosensitive material and the image-receiving material piled one on an other are conveyed with the photosensitive material jutted out from an edge of the image-receiving material. Accordingly, in the separating device of the image recording apparatus, two side parts of the photosensitive material which extend beyond the image-receiving material across the material conveying path are held so that the photosensitive material is conveyed in a direction opposite to the direction of conveyance of the image-receiving material while the direction of the conveyance of the image-receiving material is controlled with a guide board. Thereby, the photosensitive material and the image-receiving material are separated from each other.
However, this method suffers from the following problem. Both side portions of the image-receiving material can be readily separated from the photosensitive material. However, it is rather difficult to separate the central portion (in the widthwise direction) of the image-receiving material from the photosensitive material. Therefore, the image-receiving material, following the photosensitive material, is not conveyed in the predetermined direction with the result that it is abutted against the guide board. That is, jamming of the image-receiving material occurs.
This problem is attributed to the fact that, in the image recording operation, the photosensitive material and the image-receiving material piled one on another are pressurized so that the photosensitive material and the image-receiving material adhere well to each another. This tendency is significant when the photosensitive material uses a macromolecular binder of gelatin or the like.
In the conventional image-recording apparatus of Japanese patent application No. 51896/1986, the photosensitive material and the image receiving material, after being subjected to pressure transferring, are separated from each other and delivered out. More specifically, the image-recording material is conveyed to a fixing device when necessary while the photosensitive material is conveyed to a discarding section.
In general, the photosensitive material is provided in the form of a roll. That is, it is supplied from the roll to the optical exposure section and cut to a predetermined length there. However, it should be noted that the last piece of photosensitive material remaining in the roll is not always long enough for optical exposure and image transfer. If the photosensitive material shorter than the predetermined length is subjected to optical exposure and image transfer, then only part of the image is transferred onto the image-receiving material. Furthermore, if the photosensitive material is shorter than a certain length which is required for positive conveyance of the photosensitive material in the image recording apparatus, then it may be jammed during conveyance.